How to Hide GetResponse for WordPress Admin Menus

function plt_hide_getresponse_integration_menus() {
	//Hide "GetResponse".
	remove_menu_page('gr-integration');
	//Hide "GetResponse → Account".
	remove_submenu_page('gr-integration', 'gr-integration-status');
	//Hide "GetResponse → Help".
	remove_submenu_page('gr-integration', 'gr-integration-help');
	//Hide "GetResponse →".
	remove_submenu_page('gr-integration', 'gr-integration-error');
}

add_action('admin_menu', 'plt_hide_getresponse_integration_menus', 11);

Where do I put this code?